<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="../js/vue2.js"></script>
</head>
<body>
    <div id="app">
        <input type="text" v-model="first">
        <input type="text" v-model = "second">
        <!-- <p>{{first.toLowerCase().trim()+":"+second.toUperCase().trim()}}</p> -->
        <p>{{copyLs}}</p>
    </div>
</body>
<script>
    var vm=new Vue({
        el:"#app",
        data:{
            first:'',
            second:''
        },
        computed:{
            copyLs(){
                return this.first.toLowerCase().trim() +":" + this.second.toUpperCase().trim();
            }
        }
    })
</script>
</html>